When I look at a problem like this, I think of the FOIL method. This method states "You multiply integers in the order of First, Outside, Inside, Last, and then add them together"
(a -3b)(2a - 5b)
First --- 2a * a
Out --- (-5b) * a
In --- (-3b) * 2a
Last --- (-3b) * (-5b)
2a² - 5ab -6ab + 15b²
2a² - ab + 15b²
This would be your answer in simplest form!
